1. Field of the Invention
The present invention relates generally to a clamping apparatus, and more particularly to, a quick die change clamp for securing a workpiece to a work surface.
2. Description of the Related Art
Generally, a stamping press is used in industry to stamp parts such as a fender for an automotive vehicle. The stamping press includes a top ram and a bottom bolster. Either one or both the ram and bolster may have at least one, preferably a plurality of slots or keyways with a generally "T" shaped configuration. Typically, a die having die shoes is placed between the ram and bolster. The die shoe is generally a planar metal plate which may include a slot that can be aligned with a slot on either the ram or bolster.
Currently, die clamps are being used to secure or clamp workpieces such as dies, die shoes, etc. to a work surface such as the ram or bolster of a stamping press. A generally accepted description of a quick die change clamp is one that can be locked down within one half (1/2) or one hundred eighty degrees (180.degree.) of nut rotation after being "snugged" down on the workpiece. An example of such a quick die change clamp is known as the "MK Power-Nut" manufactured by Kabelschlepp America, W141 W9300 Fountain Blvd., Menomanee Falls, Wis. The MK Power-Nut includes a fastener or bolt having a head which slides in the "T" shaped slot in either the top ram or bottom bolster and the bolt may enter a slot of the die shoe if provided. The bolt has a power-nut which is hand screwed down so that solid contact with the surface of the die shoe is achieved. The power-nut includes an activation nut which is turned one hundred eighty degrees (180.degree.) with a wrench to obtain a clamping force through a complex toggle system within the power-nut to clamp or secure the die shoe to either the ram or bolster.
One disadvantage of the above quick die change clamp is that the clamp is relatively complex and costly to manufacture. Another disadvantage is that this quick die change clamp sometimes requires tightening in operation due to coming loose after operation in the press. Yet another disadvantage of the above quick die change clamp is its heavy weight.